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Now we know: Solar system has one star, eight planets (added Uranus, and Neptune), 135+moons, asteroids, comets, and meteoroids.

Pluto was added as a Planet then reduced to a Dwarf Planet

Planetary Properties

Orbital period can be observed

Distance from Sun known by Kepler’s laws

Radius known from angular size

Masses from Kepler’s 3rd

Lawas modified by Newton’

Rotation period from observations

Density can be calculated knowing radius and mass

Comparison of the Terrestrial Family of Planets to the Jovian Family of Planets

Differences between the terrestrial planets

Atmospheres and surfaceconditions are very dissimilar

Only Earth has oxygen in atmosphere and liquid water on surface

Earth and Mars rotate at about the same rate;

Venus and Mercury are much slower, and

Venus rotates in the opposite direction

Earth and Mars have moons; Mercury

and Venus don’t

Earth, Mars and Mercury have magnetic fields; Venus does not.

Interplanetary Debris

Asteroids and meteoroids are rocky; asteroids are bigger

Asteroid Eros’ the one visited by a spacecraft,

is 34 km long

Comets are icy, with some rocky parts.

One theory of Solar system formation

Cloud of gas and dust contracts due to gravity.

Conservation of Angular Momentum causesit spins faster and faster as it contracts

Condensation theory:

Interstellar dust grains help cool the cloud, and act as condensation nuclei to produceflakes

Local temperature in the condensing cloud determines where various materialscondense

Early Spacecraft Exploration of the Solar System

SovietVenera

probes landed on Venus from 1970–1978

Pioneer

andVoyager

flew through

the outer solar system.

Chapter 6

Earth

The interior of the Earth has been determined by studying the transmittal and reflection of SeismicWaves within the Earth.

Seismic waves are sound waves generated by earthquakes. They are compression waves and sinesoidalwaves. They reflect from and transmit through layer interfaces with the Earth.

The Earth has a solid iron inner core, a liquid iron outer core, a liquid rocky mantle and a solid rockycrust

Can use the pattern of reflections made during earthquakes to deduce interior structure of Earth

Crust

The crust of the Earth is divided into several plates that move with respect to each other. Themovement is driven by convection currents in the mantle. Plate movement results inearthquakes and volcanism

Interactions between the plates are:



transform, sliding against each other;



divergence, separating;



convergence, coming together.

When plates slide against each other cracks (faults) occur and earthquakes happen.

The twisting Pacific plate has produced many earthquake zones and many active volcanoes.

At divergent boundaries new crust is made.

At convergent boundaries crust is lost by subduction (sliding under) and crumpling (mountainbuilding)

The Earth’s magnetic field



appears to be generated by electric currents circulating the liquid iron core.



The trapped hot charged particles in the Van Allan belts are shunted toward the magnetic poleswhere they interact with

the air molecules. The particles are cooled by the air which glows asauroras.

The surface of the moon is heavily cratered. One of the results of the infalling bodies is topulverize the surface, thus creatinga layer debris, much of it is very fine dust. The surfaced islayered with debris on top of pulverized rock.

Most lunar craters date to at least 3.9 billion years ago; much less bombardment since then.

Craters are typically about 10 times as wide as the

meteoroid creating them, and twice as deep as theyare wide.

Early Intense Bombardment

Moon is still being bombarded by very small objects called “micrometeorites” which trends to round theedges of craters and leave a layer of dust.

Meteorites also hit

Earth; i.e. Meteor

Crater in Arizona

The great “lakes “ of liquid rock that filled the large craters are greatest evidence of vulcanism on themoon. Vulcanism ceased when the moon cooled.

This is an edge of a mare. The sooth appearance is due to the lava

that flowed up through cracks ,smoothed out then cooled.

Hadley Rill seems to be an extended lava tube whose roof has fallen in. There are other caved in lavatubes but they are much shorter

Moon’s density is relatively low, and it has no magnetic field–

cannot have sizeable iron/nickel core.Due to cooling over time the crust has thickened.

Air molecules have high speeds due to thermal motion. If the average molecular speed is well below theescape velocity, few molecules will escape.

Escape becomesmore probable:

•

for lighter molecules (higher speed for same kinetic energy)

•

at higher temperatures

•

for smaller planets (escape speed is less)

Early theories of the origin of the Moon

The currant, post Apollo, theory is the Collision Ejection Theory. Two large planetismals collide. Theircrusts splash, their interiors merge. The merged interiors become the Earth. The splashed crustalmaterial becomes the Moon

This theory accounts forthe difference in density of the Moon and Earth, the reason for the highpercentage of iron in the Earth, and the strange orbital placement.

.

Chapter 8

The Planet Mercury

Elongation of Mercury

The eccentricity of Mercury’s orbit allows to see it father from the sun sometimes.

Mercury as Seen from Earth



Synchronous rotation

1:1

Our moon

All the large moons



Mercury’s rotation 3:2

3 rotations to 2 revolutions

Comparison of Earth’s interior to that of Mercury

Mercury’s Magnetosphere

Mariner 10Trajectory

Composite of the Mariner views of Mercury

Craters and Planes (?)

Scarp (Cliff)

Edge of Caloris Basin

The spacecraft MESSENGER in orbit around Mercury. Notice the shade designed to protect theMESSENGER from the brilliant sunshine.

From its polar orbit MESSENGER is able to see the entire surface

Messenger may have found extinct volcanos

Some unusual features to be studied

Some features become more evident at different lighting

Some very strange terrain

Mercury & Dr. Einstein



Curvature of light

around a large mass



Orbital Precession

Chapter 9

Beautiful Venus

Atmosphere on Venus and on Earth

Gasses from a Volcanoon Earth

Evidence of

Eruption on

Venus

Greenhouse Effect

Greenhouse Effect on Venus

Venera

Mission

Venera Lander

Visible images from Venus by Venera

Magellan Spacecrafrt



Map of Venus by Magellan spacecraft



More of Venus’s Sphere by Magellan



Computer reconstruction

o

One Face of Venus

o

A volcanic crater

o

Craters and lava flow

o

A large volcano

o

A lava field and an impactcrater

o

These are unusual ‘pancake’ lava flows

o

Lava fields around several craters

o

Lava field

Chapter 10

The Planet Mars

Early observers did not have photography and had to draw what they saw.

In the years from about 1890 to about 1910 Percival Lowell became enamored with the observations ofSchiapereli. Canali for him were canals. He believed in canals and the intelligent life forms needed to digthem. He spent many years talking and writingabout them.

Mars’ Properties

Dist from Sun=1.5+ or app. 1.6 AU (T-B)

Year = 1.88 Earth years

Sol (Mars day) = 24h 37 m

Axis inclination = 25+ deg

Dia = .533 Earth dia

Surface gravity = .38 Earth

Surface Temp =-140 deg C to 20 deg C

Comparison of the Atmospheres

of the Terrestrial Planets

Earth

Venus

Mars

N2

0.79

2

3 x 10-4

O2

0.20

< 0.001

0-7

Ar

0.01

0.005

2 x 10-4

CO2

0.0003

64

0.009

H2O

~ 0.02

~ 0.01

~10-6

Total

1.00

90

0.01

The interior of Mars has not been studied by seismic waves. Surface clues indicate that the interior asshown is likely correct. Over time the interior has cooled and vulcanism has ceased.

The surface of Mars has been imaged and mapped at least as thoroughly as the Earth.



No liquid water has been found although there is much evidence that there has been standingand flowing water in the past.



The Southern Hemisphere is somewhat higher in elevation andcovered with craters appearing

much like The Moon.



The lower Northern Hemisphere is much more earthlike. It has giant volcanoes and canyons.

were on Earth is would stand three times higher than MountEverest and would completely cover the State of Utah



An image of a dry watershed



An image of a dry river bed



A topographic map of the mouth of a dry river entering a dry ocean



A canyon land region called South Candor



A panoramic view of a rocky rolling valley

The North Polar Cap seems to have water ice with much dry ice covering it. There is much informationin the apparent layers that have accumulated over eons.

Today



Cold



Dry

Anciently



Warm



Wet

Robots to

Mars



From the Mariner Probes in the early ‘60s to the extremely successfulCuriosity

Landerthis year,

mankind has sentavariety of robot orbiters and landers to prepare the way for a future mannedmission to the exotic Red Planet.



Viking Program

o

Two Identical Systems

o

Orbiter

o

Lander

o

Mid 70’s

o

Search for Living Life

o

Chemical not biological results

o

Red color is iron oxide

o

A view from the Viking 2 Lander in summer and winter. The occasional frost layer onlylasts until Sun up.



The Mars Global Surveyor took

images in visible and infrared of the entire planet every day forone full Mars year. Among its discoveries was this of recent gullies



One of the trickiest parts of the Mars Exploration is actually getting the rovers to Mars inworking condition.Imaginetrying to drop a sophisticated robot about 11-12 stories withoutbreaking it (or even dropping an ordinary DVD player)



When the Pathfinder lander and the Sojourner rover arrived in 1997 they began the era offaster, cheaper spacecraft. Sojourner can be seen examining the rock “Yogi”



The next generation Rovers were two, called the Spirit and Opportunity.

o

Spirit’s landing place was similar to theVikings’; this is a 360° panoramic view

o

Spirit View west from the Columbia Hills

o

This is a view from Opportunity

down into Victoria Crater. It spent nearly a full Earthyear finding the best way down into the crater and this is it.

o

Opportunity has now left Victoria Crater in search of another crater to explore.



Here we see the robotic arm at work. It cleans therock, examines it then analyses it forelements.

o

This is the Instrument complex with

the RAT, imager and spectrograph

Discoveries

–

Layering as if by water deposit

–

Spherical pebbles such as in a stream

–

Rust (color) same as the red iron oxide as in SouthernUtah

Adventures

–

Stuck in sand dune

–

Covered by dust in a storm

–

Uncovered by a whirl wind

–

Lived through a long Mars winter



Are still going strong (four times as long as expected

The Pheonix scooped up icy dirt that gave off liquid water when warmed.

EachRover has become more become bigger and more complex as we have learned how to build themand use them

Mars Pathfinder (Success)

Mars Global Surveyor (Success)

Actively taking pictures and gathering data

Mars Polar Lander (Failed)

Mars AtmosphereObserver (Failed)

2001 Mars Odyssey

-arrived Oct 24. 2001

-gathering data today

Landers (Future)

-biology and geology Laboratory

-to gather rocks and return them to Earth

Moons of Mars

Phobos (Fear) is the largerof the two.

They are both tiny and badly scarred by impacts but Phobos looks like it was nearly shattered.

The Chinese

are planning to send a robot to pick up dirt and rock samples from Diemos (Terror)to return them to Earth